Electric reversing switch

ABSTRACT

An electric reversing switch for power-operated tools has an insulating casing, the two parts of which are identical. Two onepiece contact and terminal members are mounted on each half of the casing in position for engagement by two identical movable contacts which are carried by an oscillatory contact carrier of insulating material and are stamped from sheet metal into such shape that a part of each contact is always in engagement with the two fixed contacts in one-half of the casing, while the other parts of these movable contacts engage and disengage the fixed contacts in the other part of the casing. In one position, the portion of the contacts which are always engaged also engage the fixed contacts in the other part of the casing. For maintaining the contact carrier in its two position, two ball detents each are pressed into one or the other of two depressions in each of the parts of the casing by a single spring between the two balls.

United States Patent Johnson Mar. 14, 1972 [54] ELECTRIC REVERSING SWITCH Primary Examiner-J. R. Scott [72] Inventor. David W. Johnson, Newmgton, Conn. Anomey Davis, Home, Faithful] & pg [73] Assignee: Arrow-Hart, lnc., Hartford, Conn. [22 Filed: May 13, 1970 [57] ABSTRACT An electric reversing switch for power-operated tools has an [21] Appl' 36909 insulating casing, the two parts of which are identical, Two one-piece contact and terminal members are mounted on [52] U.S.Cl. ..200/1 V, 200/155 R each half of the casing in position for engagement by two [51] Int. Cl. 4 ..H0lh 9/00 identical movable contacts which are carried by an oscillatory Field of Search -200/1 155, 11 R, 166 contact carrier of insulating material and are stamped from 200/166 168 S, l v, 155 R sheet metal into such shape that a part of each contact is always in engagement with the two fixed contacts in one-half of [56] References C'ted the casing, while the other parts of these movable contacts en- UNYTED STATES PATENTS gage and disengage the fixed contacts in the other part of the casing. In one position, the portion of the contacts which are 2,418,616 4/1947 Batcheller ..200/ 166 BB always engaged also engage the fixed contacts in the other 2,478,690 1949 'HH 6t /11 R part of the casing. For maintaining the contact carrier in its 2, 0,7 2/ 1957 y R X two position, two ball detents each are pressed into one or the 2,921,147 1960 Hun CT X other of two depressions in each of the parts of the casing by a 3, l Mastney S single spring between the two bal|s 3,242,273 3/1966 Van Der Put. ..200/168 S 3,467,80l 9/ l 969 Matthews ..200/ 166 CT X 12 Claims, 5 Drawing Figures This invention relates to electric switches, and, more particularly, to reversing switches which are particularly designed and useful in connection with motors of portable poweroperated tools and electrical equipment.

PRIOR ART In power-operated tools (as one example may be mentioned portable drills), it is often desired to reverse direction of rotation of the motor. Various switches to perform this function have been devised. Some used spring-pressed balls as the movable contact elements. Other used oscillatory switch members and various other devices as the movable contact elements. All have their advantages and drawbacks, such as multifarious parts which are difficult to assemble, or inadequate current-carrying ability through lack of firm contact engagement, or inadequate contact surface areas, or wiping of insulation onto the fixed contact surfaces as the movable contact moved from one position to another.

DESCRIPTION OF THE INVENTION It is an object of this invention to provide an improved reversing switch for electric motors of power-operated tools and the like, which is of small dimensions, which is easily assembled, which has strong contact pressure, and in which the movable contact does not wipe over insulation when engaging and disengaging the fixed contacts nor wipe insulation particles onto the contact surfaces.

Another object is to provide a switch as aforesaid which has few parts, many of which are identical in order to require a minimum of molds and dies for making the parts.

Another object is to provide a switch as aforesaid which may be easily assembled in large part, due to few parts and the identity oftheir form.

Other objects and advantages will become apparent as the invention is described in connection with the accompanying drawing.

In the drawing:

FIG. I is a top plan view ofa switch embodying the invention.

FIG. 2 is a side elevation view of the invention of FIG. 1 showing it mounted upon a power control switch.

FIG. 3 is a plan view looking into the interior of one-half (the top half) of the switch of FIG. 1 when separated from the bottom half.

FIG. 4 is an interior view similar to FIG. 3 but looking into the bottom half of the switch with the movable contact carrier in place.

FIG. 5 is a perspective view of the movable contact carrier and movable contacts as used in the invention illustrated in the foregoing figures.

Referring to the drawing, the current-carrying parts and contact-carrying element are housed with a molded insulation casing consisting of two identical halves & 20. For convenience, they will be called the top and bottom halves, respectively.

These halves are of generally rectangular shape having similar cavities (l2 and 14 in top half 10) molded in their inner faces adjacent opposite ends. Seated edgewise in recess 12 is a fixed contact and terminal member designated generally by numeral 15 which, as viewed in edge profile, is in the general shape ofa written E. The member 15 is stamped in strip form from thin, resilient sheet metal having good electrical current conductivity. One end 15t acts as a terminal portion and is bent at an angle so that its tip engages one wall 12w ofthe cavity 12 while the reentrant bend engages the opposite wall of the cavity. A small opening 17 is formed in the edge of the sidewall of the part 10 of such size and in such position as to permit insertion of the bared end of a conductor wire so that it will engage, flex and pass by the terminal end l5t and be gripped in usual fashion of wire-grip terminals.

The other end 15c of the member 15 is extended parallel and near to one sidewalljust past the transverse'midline of the casing in position to be engaged and disengaged by a movable contact. Preferably, the end portion is bent in wide-V formation to provide a line contact engagement with the movable contact member, as will hereinafter be explained.

The casing is recessed adjacent the contact end to permit flexing and that recessed area connects with the cavity 12 by a narrow passagejust fitting and receiving a bent part of the member between the contact portion 150 and the central portion of the member 15, thus tending to maintain and locate the member 15 in proper position.

The opposite end of the casing part 10 (the right end as viewed in FIG. 4) is formed in exact similarity to the left end just described but in reverse, i.e., the contact and terminal member 16 (which is identical to member 14 having terminal portion 16! and contact portion has its contact part 160 adjacent the opposite wall from 150; and conductor-wire opening 17" is diagonally opposite opening 17'.

In the center of the casing part 10, a large circular recess l0r is formed to receive an oscillatory movable contact carrier. In the bottom of this recess are formed a central bearing aperture 11, an arcuate slot 19 and two shallow spaced spherical depressions 13, the slot 19 and depressions 13 being located in circumferentially spaced positions on opposite sides of the central aperture 11 for purposes presently to be explained.

The casing half 20, being identical to the half 10 just described, needs no further description. In it the contact and terminal members equivalent to 15 and 16 are numbered 25 and 26 and wire apertures are 27', 27".

When the casing halves are put together with their recessed faces facing each other, the bottom contacts 250, 26c, will be located in positions shown in FIG. 3, while top contact 150 will lie above bottom contact 260 and top contact 160 will be above bottom contact 250.

To keep the top and bottom terminals separated in insulated relation, a thin, insulating plate whose outline is shown in dotted lines in FIG. 3 is placed between the top and bottom halves l0 and 20. Its periphery lies within the marginal edges of the halves. An aperture 29 is provided in the center to provide room for movement of the carrier30 (described below) and the parts carried thereby.

In order to connect, in one switch position, the overlying contacts, 150 and 26c and 160 and 250, respectively, and, in a second switch position, to connect the bottom front contact 25c with top back contact 150 and the bottom back contact 260 with top front contact 16c, a pair of identical bridging contacts 40 and 50 are mounted in a movable elliptical molded insulation contact carrier 30 (best illustrated in FIG. 5) which is positioned within the casing in the two aligned cooperating circular central recesses l0r, 20r.

In order that the carrier may oscillate within the casing, the carrier is provided with aligned cylindrical pivots 32 extending oppositely from the top and bottom faces of the carrier, which are received in the bearing apertures 11 and 21 (not shown) of the casing halves. To oscillate the carrier, a cylindrical boss 34, eccentrically located with respect to the axis of pivots 32, extends from one face of the carrier through the arcuate slot 19 and beyond the outer face of the top half of the casing. Embracing the outside end of the boss 34 is the bifurcated end of an operating lever 60 which is pivoted upon the outer face of the top 10 of the casing by a pivot pin 62 mounted in the top 10 and passing through an aperture in the lever. Oscillation of lever 60 will thus move boss 34 and cause oscillation of the carrier 30.

The movable bridging switch contacts are stamped from sheet metal and bent to provide a narrow strip portion, 40 and 50, to lie in narrow spaced parallel transverse slots formed in one face carrier 30, the upper face in FIG. 5. The ends, 46 and 56 respectively, of the contacts extend beyond the periphery of the carrier in diametrically opposite positions to engage and disengage the bottom fixed contacts 250, 26c. Extending from the opposite ends of each of the strip portions in a direction toward the opposite face and adjacent the periphery of the carrier are enlargements, 42 and 52, which are adapted to engage the upper and lower fixed contacts in one position of the carrier. Specifically, contact 52 will connect upper fixed contact 16c and lower fixed contact 250 while contact 42 will connect upper fixed contact 150 and lower fixed contact 260.

Extending for a short distance around the periphery of the carrier adjacent the lower edges (as viewed in FIG. 5) of each of the enlargements, contact fingers like 44 in position to maintain engagement of the movable contacts with the upper fixed contacts c, 16c, in both positions of oscillatory movement of the carrier (remembering that in FIG. 5, the carrier is upside down), are provided.

Thus, if the lever 60 be operated to cause the contact portions 42, 52 to disengage the lower fixed contacts 260, 250, the peripheral parts (such as 44) of 42 and 52 will remain in engagement with upper fixed contacts 151' and 160. With 44 engaging upper back contact l5c, current may flow between 15c and lower front contact 250 through bridging contact parts 40 and 46. Likewise, front upper contact 160 will be connected to back lower contact 26c through bridging contact parts 52,50 and 56.

it will be seen that movable contact 40 is always connected to fixed contact 150 and movable contact 50 is always connected to 160. In other words, the upper fixed contacts are always connected to the bridging contacts.

in order to maintain the contact carrier on one or the other of its two positions, a bore 36 is molded through the carrier to receive a coiled compression spring 38, both ends of which press against balls 37 urging each into one or the other of the spherical depressions 13 that are provided in both halves of the casing; thus providing a double detent action.

From the foregoing, it will be apparent that the switch requires a minimum number of parts of which the fixed contacts are identical, the bridging contacts are identical, the casing parts are identical, and the ball detents are identical.

Also, the bridging contacts have a wiping action over the fixed contacts but do not wipe over insulation and thus avoid wiping insulation particles or film over the fixed contacts, and, moreover, strong contact pressure is assured due to the V- bends in both the fixed and movable contacts.

Further, push type wire grip terminals are provided without the need to make and assemble separate parts.

Modifications within the scope of the invention will occur to those skilled in the art. Therefore, the invention is not limited to the precise forms and arrangement of parts illustrated and described.

What is claimed is:

1. An electric reversing switch comprising:

an insulating casing including two halves, each of said casing halves having a central recess;

a first pair of fixed contact members supported in one casing half adjacent opposite ends, a contact portion extending into said central recess;

a second pair comprising third and fourth fixed contact members supported in the other casing half adjacent opposite ends in insulated relation to said first pair, said third and fourth contact members each having a contact portion extending into said central recess;

an oscillatory insulation contact carrier pivotally mounted on said casing halves within said central recesses; and

a pair ofbridging contact members mounted on said contact carrier, each of said bridging contact members having a first contact portion for constant engagement with a different one of said first pair of fixed contacts and second contact portion for engagement with one of said third or said fourth fixed contacts dependent upon the position of said oscillatory insulation contact carrier, whereby oscillation of said contact carrier connects each of said fixed contacts of said first pair to said third or to said fourth fixed contact.

2. A switch as claimed in claim 1 in which the bridging con tact members are identical. I

3. A switch as claimed 1n clalm 1 in which all the fixed contact members are identical.

4. A switch as claimed in claim 3 in which the bridging contact members are resilient sheet metal stampings and have terminal portions adapted to bite into and grip the bared end ofa conductor wire between itself and a wall of said casing, and said casing halves have openings adjacent said terminal ends for insertion of said conductor wires.

5. A switch as claimed in claim 1 in which the casing halves are identical.

6. A switch as claimed in claim 5 in which all the fixed contact members are identical.

7. A switch as claimed in claim 5 in which the bridging contacts are identical.

8. A switch as claimed in claim 7 having two detent means supported in said carrier and biased by a single spring, and means in each of said halves to receive said detent means in two different positions of said carrier.

9. A switch as claimed in claim 1 in which the contact carrier has spaced slots in one face in which portions of said bridging contact members are received, said constantly engaging surfaces of each bridging contact member extend beyond different ends of the slots, and a contacting surface of each bridging contact member extends beyond the opposite end of each slot.

10. A switch as claimed in claim 1 having two detent means supported in said carrier and biased by a single spring, and means in each of said halves to receive said detent means in two different positions ofsaid carrier.

11. A switch as claimed in claim 1 having a boss on said carrier eccentric with respect to the oscillatory axis of said carrier and extending through a slot in one casing half, and an operating lever pivotally mounted on said one casing half and engaging said boss.

12. A switch as claimed in claim 1 wherein the casing halves are substantially rectangular and identical, and the fixed contact members are identical, each casing half having two fixed contact members mounted edgewise in diagonally opposite corners, said members contacting portions extending along opposite edges of the casing. 

1. An electric reversing switch comprising: an insulating casing including two halves, each of said casing halves having a central recess; a first pair of fixed contact members supported in one casing half adjacent opposite ends, a contact portion extending into said central recess; a second pair comprising third and fourth fixed contact members supported in the other casing half adjacent opposite ends in insulated relation to said first pair, said third and fourth contact members each having a contact portion extending into said central recess; an oscillatory insulation contact carrier pivotally mounted on said casing halves within said central recesses; and a pair of bridging contact members mounted on said contact carrier, each of said bridging contact members having a first contact portion for constant engagement with a different one of said first pair of fixed contacts and second contact portion for engagement with one of said third or said fourth fixed contacts dependent upon the position of said oscillatory insulation contact carrier, whereby oscillation of said contact carrier connects each of said fixed contacts of said first pair to said third or to said fourth fixed contact.
 2. A switch as claimed in claim 1 in which the bridging contact members are identical.
 3. A switch as claimed in claim 1 in which all the fixed contact members are identical.
 4. A switch as claimed in claim 3 in which the bridging contact members are resilient sheet metal stampings and have terminal portions adapted to bite into and grip the bared end of a conductor wire between itself and a wall of said casing, and said casing halves have openings adjacent said terminal ends for insertion of said conductor wires.
 5. A switch as claimed in claim 1 in which the casing halves are identical.
 6. A switch as claimed in claim 5 in which all the fixed contact members are identical.
 7. A switch as claimed in claim 5 in which the bridging contacts are identical.
 8. A switch as claimed in claim 7 having two detent means supported in said carrier and biased by a single spring, and means in each of said halves to receive said detent means in two different positions of said carrier.
 9. A switch as claimed in claim 1 in which the contact carrier has spaced slots in one face in which portions of said bridging contact members are received, said constantly engaging surfaces of each bridging contact member extend beyond different ends of the slots, and a contacting surface of each bridging contact member extends beyond the opposite end of each slot.
 10. A switch as claimed in claim 1 having two detent means supported in said carrier and biased by a single spring, and means in each of said halves to receive said detent means in two different positions of said carrier.
 11. A switch as claimed in claim 1 having a boss on said carrier eccentric with respect to the oscillatory axis of said carrier and extending through a slot in one casing half, and an operating lever pivotally mounted on said one casing half and engaging said boss.
 12. A switch as claimed in claim 1 wherein the casing halves are substantially rectangular and identical, and the fixed contact members are identical, each casing half having two fixed contact members mounted edgewise in diagonally opposite corners, said members contacting portions extending along opposite edges of the casing. 